Nice write up. I have an employee that we just terminated and a document she worked with everyday was locked for editing. We rebooted the machine she was logged in to but that didn't fix the problem. This did just the trick. Thanks!

I had the same issue where and Excel file was saying that it was locked or Read-Only by me. I have tried to look for open files but nothing will show, I even restart my computer and the file still show as lock. I did some research and found that the file was still open on the following path: C:\Users\name\AppData\Roaming\Microsoft\Excel\ once you file your file just delete it and will open up normally.

Cool - Now I know about File Services in server manager.
I still find the old way easy-peasy
I usually start by right clicking "Computer" and selecting Manage, Then in the computer management console, I "Connect to another computer" (The server).
From there, I expand System Tools > Shared Folders > Open files.
Then I find the file and unlock it by right clicking on it and selecting "Close open Files"

Like OldSpice above, I do this all from Computer Management on my local PC. Don't even need RSAT. With Windows 10, they added the connection to Computer Management by right-clicking on the Start button. Connect to Other Computer, type in my file server, System Tools, Shared Folders, and Bob's your uncle.

I do this all the time when I'm making tweaks to our MS Access front end and I need to kick people out to save the ADE file.